Magma Storage and Extraction Associated with Plinian and Interplinian Activity at Santorini Caldera (Greece)
Magma Storage and Extraction Associated with Plinian and Interplinian Activity at Santorini Caldera (Greece)
复制标题
与圣托里尼火山口（希腊）的普林阶和间阶活动相关的岩浆储存和提取
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
A. Cadoux
中科院分区：
文献类型：
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作者：
T. Druitt;M. Mercier;L. Florentin;E. Deloule;N. Cluzel;T. Flaherty;E. Médard;A. Cadoux
圣托里尼破火山口有着悠久的普林尼期喷发和破火山口坍塌的历史，相隔20 -40 kyr的普林尼期。我们已经进行了一项研究，以限制火山口下的岩浆储存/提取深度。我们分析了20万年以来来自于普宁期和间普宁期产物的138个橄榄石、辉石和斜长石包裹体中的H_2O，以及这些包裹体中的CO_2、S、Cl、F和dD。该数据集包括公元前世纪末米诺斯普林尼火山喷发产物中的64个包裹体。熔体包裹体均呈孤立的椭球形，无挥发分渗漏的结构证据。镁铁质熔体包裹体含H_2O 1- 4wt%，CO_2高达1200 ppm，S高达1200 ppm，Cl高达2000 ppm，F高达400 ppm;镁铁质包裹体含H_2O 2- 7wt%，CO_2高达150 ppm，S高达400 ppm，Cl高达2000- 6000 ppm，F高达600- 1000 ppm。27个代表性包裹体的dD值（-37 ~-104%）介于地幔和板片之间，排除了橄榄石包裹体中氢扩散造成的H2O损失。H_2O、S和Cl在镁铁质-镁铁质熔体包裹体中的分布不均匀，说明许多熔体包裹体的包裹作用是在挥发分饱和的条件下进行的。大多数Santorinimelts饱和在一个自由COHSCl蒸汽相深度小于10公里，唯一的例外是玄武岩熔体从一个单一的interplinian喷发，这是挥发性不饱和高达K2 O含量的1重量%。米诺斯火山喷发的流纹岩熔体中可能含有一种游离的高盐液相。H2O和CO2饱和压力计算使用适当calibratedsolubility模型估计喷发前岩浆储存深度。来自米诺斯火山的流纹英岩浮石中的斜长石斑晶，其核部含有捕获于10- 12 km（320 MPa）深处的熔融包裹体，边缘（也包括斜方辉石和单斜辉石）含有捕获于4- 6 km（100-160 MPa）深处的包裹体。这记录了晚期硅补充4公里）。公元726年卡梅尼火山喷发的熔融包裹体产生了4 km的喷发前储存深度，这与2011-2012年破火山口动荡期间膨胀源的大地测量数据估计的深度相似;这支持了动荡的岩浆起源。前AD 726岩浆存储benethKameni的水平比早期的Escherichiinterplinian喷发更深，也许是由于米诺斯喷发引起的地壳应力的变化。结合先前发表的结果，熔融包裹体数据提供了一个地壳铅垂系统的时间积分图像。幔源玄武岩注入下地壳，在那里它们破裂产生热晶体泥体中的演化熔体。演化后的残余熔体在8至> 15公里深的区间内与其母岩浆分离，然后迅速上升到地壳上部，在那里它们要么结晶，要么积累为可喷发的贫结晶岩浆体。
Santorini caldera has had a long history of plinian eruptions and caldera collapses, separated by20–40 kyr interplinian periods. We have carried out a study to constrain magma storage/extractiondepths beneath the caldera. We analysed H2O in 138 olivine-, pyroxene- and plagioclase-hostedmelt inclusions from plinian and interplinian products from the last 200 kyr, and CO2, S, Cl, F anddD in various subsets of these. The dataset includes 64 inclusions in products of the Minoan plinianeruption of the late 17th century BCE. All the melt inclusions were ellipsoidal and isolated, with notextural evidence for volatile leakage. Mafic melt inclusions contain 1–4 wt % H2O and up to1200ppm CO2, 1200ppm S, 2000ppm Cl and 400ppm F; silicic inclusions contain 2–7 wt % H2O, upto 150ppm CO2, up to 400ppm S, 2000–6000ppm Cl and 600–1000ppm F. The dD values of 27 representativeinclusions (–37 to –104%) are intermediate between mantle and slab values and ruleout significant H2O loss by hydrogen diffusion from olivine-hosted inclusions. H2O, S and Cl behavecompatibly in melt inclusion suites varying from mafic to silicic in composition, showing thatentrapment of many melt inclusions took place under volatile-saturated conditions. Most Santorinimelts are saturated in a free COHSCl vapour phase at depths of less than 10 km; the only exceptionsare basaltic melts from a single interplinian eruption, which were volatile-undersaturated upto K2O contents of 1 wt %. The rhyolitic melt of the Minoan eruption probably contained a freehypersaline liquid phase. H2OþCO2 saturation pressures were calculated using suitably calibratedsolubility models to estimate pre-eruptive magma storage depths. Magmas feeding plinian eruptionswere stored at >4km (>100 MPa) and extracted over depth intervals of several kilometres.Plagioclase phenocrysts in rhyodacitic pumice from the Minoan eruption have cores containingmelt inclusions trapped at depths up to 10–12km (320 MPa), and rims (also orthopyroxene andclinopyroxene) containing inclusions trapped at 4–6km (100–160 MPa). This records late-stage silicicreplenishment of a 4 km). Melt inclusions fromthe AD 726 eruption of Kameni Volcano yield a pre-eruptive storage depth of 4 km, which is similarto that estimated from geodetic data for the inflation source during the 2011–2012 period of caldera unrest; this supports a magmatic origin of the unrest. The level of pre-AD 726 magma storage beneathKameni was deeper than that of earlier silicic interplinian eruptions, perhaps owing tochanges in crustal stress caused by the Minoan eruption. Combined with previously published results,the melt inclusion data provide a time-integrated image of the crustal plumbing system.Mantle-derived basalts are injected into the lower crust, where they fractionate to produce evolvedmelts in bodies of hot crystal mush. Evolved residual melts separate from their parent mushes inthe 8 to >15km depth interval, then ascend rapidly into the upper crust, where they either crystallizeor accumulate as bodies of eruptible, crystal-poor magma.
影响因子：
18.3
作者：
M. Parks;J. Biggs;P. England;T. Mather;P. Nomikou;Kirill Palamartchouk;X. Papanikolaou;D. Paradissis;B. Parsons;D. Pyle;Costas Raptakis;V. Zacharis
通讯作者：
M. Parks;J. Biggs;P. England;T. Mather;P. Nomikou;Kirill Palamartchouk;X. Papanikolaou;D. Paradissis;B. Parsons;D. Pyle;Costas Raptakis;V. Zacharis
DOI：
10.1144/sp410.13
发表时间：
2014-11
期刊：
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影响因子：
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作者：
G. Zellmer;M. Edmonds;S. Straub
通讯作者：
G. Zellmer;M. Edmonds;S. Straub
影响因子：
5.3
作者：
Hartley, Margaret E.;Maclennan, John;Thordarson, Thor
通讯作者：
Thordarson, Thor